Process of making nitrates.



UNITED STAWENT rnc I CARL BOSCH AND WILI-TELM WILD, F LUDWIGSHAFEN-ON-THE-RHINE, GERMANY,

ASSIG-NORS TO BADISCHE ANILIN & SODA FABRIK, OF LUDWIGSHAFEN-ON-THE-RHTNE, GERMANY, A CORPORATION.

PROCESS OF MAKING NITRA'IES.

No Drawing.

To all whom 'it may concern:

Be it known that we, CARL Boson, Ph. D., and VVILHELM WILD, Ph. D.,chemists, subjects, respectively, of the King of Prussia and the GrandDuke of Baden, residing at Ludwigshafen-on-the-Rhine, Germany, haveinvented new and useful Improvements in Processes of Making Nitrates, ofwhich the following is a specification.

Our invention relates to the production of nitrates.

We have discovered that if a solution containing a nitrite, either aloneor mixed with a nitrate, be treated with a mixture of gases containing ahigher oxid of nitrogen and oxygen, the nitrite can be converted intonitrate. Under the term higher oxid of nitrogen we include all the oxideof nitrogen except nitrous oxid (N 0).

Our invention is of particular use for the treatment of mixtures ofnitrite and nitrate such as are generallyobt-ained when the nitrousgases produced by passing air through an electric discharge are causedto act on a base, either in a solid form or in a state of solution orsuspension.

The process of our invention possesses certain advantages over theprocess for absorbing oxids of nitrogen with water with the productionof nitric acid, since smaller apparatus can be employed and further theabsorption of the nitrous gases proceeds more rapidly when a neutral ornearly neutral solution be employed, such as is the case in the presentinvention, than when the said nitrous gases are treated with a more orless concentrated nitric acid. The process be understood as in any waylimiting the invention to the example given.

Allow a Specification of Letters Patent.

Patented Jan. 9, 1912.

Application filed December 7, 1909. Serial No. 531,869.

solution containing sixteen and three-tenths .per cent. of calciumnitrate and eighteen per cent. of calcium nitrite to trickle down anabsorbing tower which is packed with suitable material and at the sametime pass through the tower a curr nt of gases consesses a temperatureof fifty-six degrees centrigrade and leaves atthirty degrees centigrade,while the solution possesses a'temperature of. from eighteen to twentydegrees centigrade on entering and of about from twenty-eight to thirtydegrees centigrade on leaving. The oxidation of the nitrite may becomplete after the solution has passed once through the tower or it maybe necessary to pass the solution more than once through the tower, orthrough more than one tower, according to the quantity of solution usedand the rate at which it as well as the gases flow. The completion ofthe oxidation can be ascertained by analysis and also by the solution,which was previously yellow, becoming colorless. It is then found tocontain forty-six and a half per cent. of calcium nitrate and onlyseventeen hundredths per cent. of calcium nitrite, that is to say, boththe oxidation of the nitrite andthe evaporation of a part of the waterhave taken place at the same time. The solution containing calciumnitrate and calcium nitrite employed according to this example can beobtained, for instance, by absorbing dilute nitrous gases by meansofmilk of lime;

Now what we claim is 1. The process of producing nitrate by 3. Theprocess of producing practically set our hands in the presence of twosubpure calcium nitrate by treating a solution scribing Witnesses.

containing calcium nitrite and calcium CARL BOSCH. nitrate wlth agaseous mixture containing 3 WILHELM WILD. 5 an oxid of nitrogen andoxygen substan- Witnesses: f tially as hereinbefore described. J. AutoLLOYD,

In testimony whereof we have hereunto W. W. SCHMIDT.

